The present invention relates to image processing apparatus in which image data conversion is tested automatically by wrapping test image data.
An image processing apparatus, such as, for example, a multimedia computer system, typically comprises an image capture adaptor having an analog to digital (A to D) convertor for digitizing successive frames of an analog video signal generated by a video source such as a video camera, video tape player or the like. The digitized frames are usually stored in a memory of the computer system from which they can be accessed and modified under the control of application software before transfer, via an digital to analog (D to A) convertor in the image capture adaptor, to an analog video output device such as a visual display unit, video tape recorder or the like.
The digitized frames can be degraded during both capture and replay operations. Specifically, individual pixels of the image frames can be degraded by quantization errors introduced by the D to A and A to D conversion hardware. Signal amplification during both capture and replay operations can also degrade the image frames. The degradation is conventionally identified manually by visual inspection of replayed images. However, such inspection is extremely subjective and may be adversely affected by environmental factors such as, for example, ambient lighting. Furthermore, it may not be possible to distinguish, by visual inspection, between faults located in the conversion hardware and faults located in the amplification hardware.